记录一些js实用到码片段

摘自今日头条，一些以后可能会用到的代码片段。

1. 原生JavaScript实现字符串长度截取

function cutstr(str, len) {
 var temp;
 var icount = 0;
 var patrn = /[^\x00-\xff]/; // 匹配双字节字符(包括汉字在内)
 var strren = "";
 for (var i = 0; i < str.length; i++) {
   if (icount < len - 1) {
   temp = str.substr(i, 1);
   if (patrn.exec(temp) == null) {
   icount = icount + 1;
   } else {
   icount = icount + 2;
   }
   } else {
   break;
  }
  }
 return strre + "...";
}

2. 原生JavaScript获取域名主机

function getHost(url) {
 var host = "null";
 if (typeof url == undefined || url === null) {
 url = window.location.href;
 }
 var regex = /^w+://([^/]*).*/;
 var match = url.match(regex);
 if (typeof match != undefined && match != null) {
 host = match[1];
 }
 return host;
}

3. 原生JavaScript清除空格

String.prototype.trim = function() {
 var reExtraSpace = /^s*(.*?)s+$/;
 return this.replace(reExtraSpace, "$1");
}

4. 原生JavaScript替换全部

String.prototype.replaceAll = function(s1, s2) {
 return this.replace(new RegExp(s1, "gm"), s2);
}

5. 原生JavaScript转义html标签

function HtmlEncode(text) {
 return text.replace(/&/g, '&amp')
 .replace(/"/g, '&quot')
 .replace(/</g, '&lt')
 .replace(/>/g, '&gt');
}

6. 原生JavaScript还原html标签

function HtmlDecode(text) {
 return text.replace('&amp', /&/g)
 .replace('&quot', /"/g)
 .replace('&lt', /</g)
 .replace('&gt', />/g);
}
7. 原生JavaScript时间日期格式替换
```javascript
Date.prototype.Format = function(formatStr) {
 var str = formatStr;
 var Week = ['日', '一', '二', '三', '四', '五', '六'];
 str = str.replace(/yyyy|YYYY/, this.getFullYear());
 str = str.replace(/yy|YY/, (this.getYear() % 100) > 9 ? (this.getYear() % 100).toString() : '0' + (this.getYear() % 100));
 str = str.replace(/MM/, (this.getMonth() + 1) > 9 ? (this.getMonth() + 1).toString() : '0' + (this.getMonth() + 1));
 str = str.replace(/M/g, (this.getMonth() + 1));
 str = str.replace(/w|W/g, Week[this.getDay()]);
 str = str.replace(/dd|DD/, this.getDate() > 9 ? this.getDate().toString() : '0' + this.getDate());
 str = str.replace(/d|D/g, this.getDate());
 str = str.replace(/hh|HH/, this.getHours() > 9 ? this.getHours().toString() : '0' + this.getHours());
 str = str.replace(/h|H/g, this.getHours());
 str = str.replace(/mm/, this.getMinutes() > 9 ? this.getMinutes().toString() : '0' + this.getMinutes());
 str = str.replace(/m/g, this.getMinutes());
 str = str.replace(/ss|SS/, this.getSeconds() > 9 ? this.getSeconds().toString() : '0' + this.getSeconds());
 str = str.replace(/s|S/g, this.getSeconds());
 return str
 }

8. 原生JavaScript判断是否为数字类型

function isDigit(value) {
 var patrn = /^[0-9]*$/;
 if (patrn.exec(value) == null || value == "") {
 return false
 } else {
 return true
 }
}

9. 原生JavaScript设置cookie值

function setCookie(name, value, Hours) {
 var d = new Date();
 var offset = 8;
 var utc = d.getTime() + (d.getTimezoneOffset() * 60000);
 var nd = utc + (3600000 * offset);
 var exp = new Date(nd);
 exp.setTime(exp.getTime() + Hours * 60 * 60 * 1000);
 document.cookie = name + "=" + escape(value) + ";path=/;expires=" + exp.toGMTString() + ";domain=360doc.com;"
}

10. 原生JavaScript获取cookie值

function getCookie(name) {
 var arr = document.cookie.match(new RegExp("(^| )" + name + "=([^;]*)(;|$)"));
 if (arr != null) return unescape(arr[2]);
 return null
}

11. 原生JavaScript加入收藏夹

function AddFavorite(sURL, sTitle) {
 try {
 window.external.addFavorite(sURL, sTitle)
 } catch(e) {
 try {
 window.sidebar.addPanel(sTitle, sURL, "")
 } catch(e) {
 alert("加入收藏失败，请使用Ctrl+D进行添加")
 }
 }
}

12. 原生JavaScript设为首页

function setHomepage() {
 if (document.all) {
 document.body.style.behavior = 'url(#default#homepage)';
 document.body.setHomePage('http://***');
 } else if (window.sidebar) {
 if (window.netscape) {
 try {
 netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect")
 } catch(e) {
 alert("该操作被浏览器拒绝，如果想启用该功能，请在地址栏内输入 about:config,然后将项 signed.applets.codebase_principal_support 值该为true")
 }
 }
 var prefs = Components.classes['@mozilla.org/preferences-service;1'].getService(Components.interfaces.nsIPrefBranch);
 prefs.setCharPref('browser.startup.homepage', 'http://***')
 }
}

13. 原生JavaScript判断IE6

var ua = navigator.userAgent.toLowerCase();
var isIE6 = ua.indexOf("msie 6") > -1;
if (isIE6) {
 try {
 document.execCommand("BackgroundImageCache", false, true)
 } catch(e) {}
}

14. 原生JavaScript加载样式文件

function LoadStyle(url) {
 try {
 document.createStyleSheet(url)
 } catch(e) {
 var cssLink = document.createElement('link');
 cssLink.rel = 'stylesheet';
 cssLink.type = 'text/css';
 cssLink.href = url;
 var head = document.getElementsByTagName('head')[0];
 head.appendChild(cssLink)
 }
}

15. 原生JavaScript返回脚本内容

function evalscript(s) {
 if(s.indexOf('<script') == -1) return s;
 var p = /<script[^>]*?>([^\x00]*?)</script>/ig;
 var arr = [];
 while(arr = p.exec(s)) {
 var p1 = /<script[^>]*?src="([^>]*?)"[^>]*?(reload="1")?(?:charset="([w-]+?)")?></script>/i;
 var arr1 = [];
 arr1 = p1.exec(arr[0]);
 if(arr1) {
 appendscript(arr1[1], '', arr1[2], arr1[3]);
 } else {
 p1 = /<script(.*?)>([^\x00]+?)</script>/i;
 arr1 = p1.exec(arr[0]);
 appendscript('', arr1[2], arr1[1].indexOf('reload=') != -1);
 }
 }
 return s;
}

16. 原生JavaScript清除脚本内容

function stripscript(s) {
 return s.replace(/<script.*?>.*?</script>/ig, '');
}

17. 原生JavaScript动态加载脚本文件

function appendscript(src, text, reload, charset) {
 var id = hash(src + text);
 if(!reload && in_array(id, evalscripts)) return;
 if(reload && $(id)) {
 $(id).parentNode.removeChild($(id));
 }
 
 evalscripts.push(id);
 var scriptNode = document.createElement("script");
 scriptNode.type = "text/javascript";
 scriptNode.id = id;
 scriptNode.charset = charset ? charset : (BROWSER.firefox ? document.characterSet : document.charset);
 try {
 if(src) {
 scriptNode.src = src;
 scriptNode.onloadDone = false;
 scriptNode.onload = function () {
 scriptNode.onloadDone = true;
 JSLOADED[src] = 1;
 };
 scriptNode.onreadystatechange = function () {
 if((scriptNode.readyState == 'loaded' || scriptNode.readyState == 'complete') && !scriptNode.onloadDone) {
 scriptNode.onloadDone = true;
 JSLOADED[src] = 1;
 }
 };
 } else if(text){
 scriptNode.text = text;
 }
 document.getElementsByTagName('head')[0].appendChild(scriptNode);
 } catch(e) {}
}

18. 原生JavaScript返回按ID检索的元素对象

function $(id) {
 return !id ? null : document.getElementById(id);
}

19. 原生JavaScript返回浏览器版本内容

function browserVersion(types) {
 var other = 1;
 for(i in types) {
 var v = types[i] ? types[i] : i;
 if(USERAGENT.indexOf(v) != -1) {
 var re = new RegExp(v + '(\/|\s)([\d\.]+)', 'ig');
 var matches = re.exec(USERAGENT);
 var ver = matches != null ? matches[2] : 0;
 other = ver !== 0 && v != 'mozilla' ? 0 : other;
 }else {
 var ver = 0;
 }
 eval('BROWSER.' + i + '= ver');
 }
 BROWSER.other = other;
}

20. 原生JavaScript元素显示的通用方法

function $(id) {
 return !id ? null : document.getElementById(id);
}
function display(id) {
 var obj = $(id);
 if(obj.style.visibility) {
 obj.style.visibility = obj.style.visibility == 'visible' ? 'hidden' : 'visible';
 } else {
 obj.style.display = obj.style.display == '' ? 'none' : '';
 }
}

21. 原生JavaScript中有insertBefore方法,可惜却没有insertAfter方法?用如下函数实现

function insertAfter(newChild, refChild) {
 var parElem = refChild.parentNode; 
 if(parElem.lastChild == refChild){ 
 refChild.appendChild(newChild); 
 }else{ 
 parElem.insertBefore(newChild, refChild.nextSibling); 
 } 
}

22. 原生JavaScript中兼容浏览器绑定元素事件

function addEventSamp(obj, evt, fn){ 
 if (obj.addEventListener) { 
 obj.addEventListener(evt, fn, false); 
 }else if(obj.attachEvent){ 
 obj.attachEvent('on' + evt, fn); 
 } 
}

23. 原生JavaScript光标停在文字的后面，文本框获得焦点时调用

function focusLast(){ 
 var e = event.srcElement; 
 var r =e.createTextRange(); 
 r.moveStart('character',e.value.length); 
 r.collapse(true); 
 r.select(); 
}

24. 原生JavaScript检验URL链接是否有效

function getUrlState(URL) { 
 var xmlhttp = new ActiveXObject("microsoft.xmlhttp"); 
 xmlhttp.Open("GET", URL, false); 
 try { 
 xmlhttp.Send(); 
 } catch(e) {
 
 } finally { 
 var result = xmlhttp.responseText; 
 if(result) { 
 if(xmlhttp.Status==200){ 
 return true; 
 }else{ 
 return false; 
 } 
 } else { 
 return false; 
 } 
 } 
}

25. 原生JavaScript格式化CSS样式代码

function formatCss(s){ //格式化代码
 s = s.replace(/s*([{}:;,])s*/g, "$1");
 s = s.replace(/;s*;/g, ";"); //清除连续分号
 s = s.replace(/,[s.#d]*{/g, "{");
 s = s.replace(/([^s]){([^s])/g, "$1 {
    $2");
 s = s.replace(/([^s])}([^
]*)/g, "$1
}
$2");
 s = s.replace(/([^s]);([^s}])/g, "$1;
    $2");
 return s;
}

26. 原生JavaScript压缩CSS样式代码

function yasuoCss (s) { //压缩代码
 s = s.replace(//*(.|
)*?*//g, ""); //删除注释
 s = s.replace(/s*([{}:;,])s*/g, "$1");
 s = s.replace(/,[s.#d]*{/g, "{"); //容错处理
 s = s.replace(/;s*;/g, ";"); //清除连续分号
 s = s.match(/^s*(S+(s+S+)*)s*$/); //去掉首尾空白
 return (s == null) ? "" : s[1];
}

27. 原生JavaScript获取当前路径

var currentPageUrl = "";
if (typeof this.href === undefined) {
 currentPageUrl = document.location.toString().toLowerCase();
}
else {
 currentPageUrl = this.href.toString().toLowerCase();
}

28. 原生JavaScript将IP地址转成整型

function _ip2int(ip){
 var num = 0;
 ip = ip.split(".");
 num = Number(ip[0]) * 256 * 256 * 256 + Number(ip[1]) * 256 * 256 + Number(ip[2]) * 256 + Number(ip[3]);
 num = num >>> 0;
 return num;
}

29. 原生JavaScript整型解析为IP地址

function _int2iP(num){
 var str;
 var tt = new Array();
 tt[0] = (num >>> 24) >>> 0;
 tt[1] = ((num << 8) >>> 24) >>> 0;
 tt[2] = (num << 16) >>> 24;
 tt[3] = (num << 24) >>> 24;
 str = String(tt[0]) + "." + String(tt[1]) + "." + String(tt[2]) + "." + String(tt[3]);
 return str;
}

30. 原生JavaScript实现checkbox全选与全不选

function checkAll() {
 var selectall = document.getElementById("selectall");
 var allbox = document.getElementsByName("allbox");
 if (selectall.checked) {
 for (var i = 0; i < allbox.length; i++) {
 allbox[i].checked = true;
 }
 } else {
 for (var i = 0; i < allbox.length; i++) {
 allbox[i].checked = false;
 }
 }
}

31. 原生JavaScript判断是否移动设备

function isMobile(){
 if (typeof this._isMobile === 'boolean'){
 return this._isMobile;
 }
 var screenWidth = this.getScreenWidth();
 var fixViewPortsExperiment = rendererModel.runningExperiments.FixViewport || rendererModel.runningExperiments.fixviewport;
 var fixViewPortsExperimentRunning = fixViewPortsExperiment && (fixViewPortsExperiment.toLowerCase() === "new");
 if(!fixViewPortsExperiment){
 if(!this.isAppleMobileDevice()){
 screenWidth = screenWidth/window.devicePixelRatio;
 }
 }
 var isMobileScreenSize = screenWidth < 600;
 var isMobileUserAgent = false;
 this._isMobile = isMobileScreenSize && this.isTouchScreen();
 return this._isMobile;
}

32. 原生JavaScript判断是否移动设备访问

function isMobileUserAgent() {
 return (/iphone|ipod|android.*mobile|windows.*phone|blackberry.*mobile/i.test(window.navigator.userAgent.toLowerCase()));
}

33. 原生JavaScript判断是否苹果移动设备访问

function isAppleMobileDevice() {
 return (/iphone|ipod|ipad|Macintosh/i.test(navigator.userAgent.toLowerCase()));
}

34. 原生JavaScript判断是否安卓移动设备访问

function isAndroidMobileDevice(){
 return (/android/i.test(navigator.userAgent.toLowerCase()));
}

35. 原生JavaScript判断是否Touch屏幕

function isTouchScreen() {
 return (('ontouchstart' in window) || window.DocumentTouch && document instanceof DocumentTouch);
}

36. 原生JavaScript判断是否在安卓上的谷歌浏览器

function isNewChromeOnAndroid(){
 if(this.isAndroidMobileDevice()){
 var userAgent = navigator.userAgent.toLowerCase();
 if((/chrome/i.test(userAgent))){
 var parts = userAgent.split('chrome/');
 var fullVersionString = parts[1].split(" ")[0];
 var versionString = fullVersionString.split('.')[0];
 var version = parseInt(versionString);
 if(version >= 27){
 return true;
 }
 }
 }
 return false;
}

37. 原生JavaScript判断是否打开视窗

function isViewportOpen() {
 return !!document.getElementById('wixMobileViewport');
}

38. 原生JavaScript获取移动设备初始化大小

function getInitZoom() {
 if(!this._initZoom) {
 var screenWidth = Math.min(screen.height, screen.width);
 if(this.isAndroidMobileDevice() && !this.isNewChromeOnAndroid()) {
 screenWidth = screenWidth / window.devicePixelRatio;
 }
 this._initZoom = screenWidth /document.body.offsetWidth;
 }
 return this._initZoom;
}

39. 原生JavaScript获取移动设备最大化大小

function getZoom(){
 var screenWidth = (Math.abs(window.orientation) === 90) ? Math.max(screen.height, screen.width) : Math.min(screen.height, screen.width);
 if(this.isAndroidMobileDevice() && !this.isNewChromeOnAndroid()){
 screenWidth = screenWidth/window.devicePixelRatio;
 }
 var FixViewPortsExperiment = rendererModel.runningExperiments.FixViewport || rendererModel.runningExperiments.fixviewport;
 var FixViewPortsExperimentRunning = FixViewPortsExperiment && (FixViewPortsExperiment === "New" || FixViewPortsExperiment === "new");
 if(FixViewPortsExperimentRunning){
 return screenWidth / window.innerWidth;
 }else{
 return screenWidth / document.body.offsetWidth;
 }
}

40. 原生JavaScript获取移动设备屏幕宽度

function getScreenWidth(){
 var smallerSide = Math.min(screen.width, screen.height);
 var fixViewPortsExperiment = rendererModel.runningExperiments.FixViewport || rendererModel.runningExperiments.fixviewport;
 var fixViewPortsExperimentRunning = fixViewPortsExperiment && (fixViewPortsExperiment.toLowerCase() === "new");
 if(fixViewPortsExperiment){
 if(this.isAndroidMobileDevice() && !this.isNewChromeOnAndroid()){
 smallerSide = smallerSide/window.devicePixelRatio;
 }
 }
 return smallerSide;
}

41. 原生JavaScript完美判断是否为网址

function IsURL(strUrl) {
 var regular = /^(((https?|ftp)://)?[-a-z0-9]+(.[-a-z0-9]+)*.(?:com|edu|gov|int|mil|net|org|biz|info|name|museum|asia|coop|aero|[a-z][a-z]|((25[0-5])|(2[0-4]d)|(1dd)|([1-9]d)|d))(/[-a-z0-9_:@&?=+,.!/~%$]*)?)$/i
 if (regular.test(strUrl)) {
 return true;
 }
 else {
 return false;
 }
}

42. 原生JavaScript根据样式名称检索元素对象

function getElementsByClassName(name) {
 var tags = document.getElementsByTagName('*') || document.all;
 var els = [];
 for (var i = 0; i < tags.length; i++) {
 if (tags[i].className) {
 var cs = tags[i].className.split(' ');
 for (var j = 0; j < cs.length; j++) {
 if (name == cs[j]) {
 els.push(tags[i]);
 break;
 }
 }
 }
 }
 return els;
}

43. 原生JavaScript判断是否以某个字符串开头

String.prototype.startWith = function (s) {
 return this.indexOf(s) == 0;
}

44. 原生JavaScript判断是否以某个字符串结束

String.prototype.endWith = function (s) {
 var d = this.length - s.length;
 return (d >= 0 && this.lastIndexOf(s) == d);
}

45. 原生JavaScript返回IE浏览器的版本号

function getIE(){
 if (window.ActiveXObject){
 var v = navigator.userAgent.match(/MSIE ([^;]+)/)[1];
 return parseFloat(v.substring(0, v.indexOf(".")));
 }
 return false;
}

46. 原生JavaScript获取页面高度

function getPageHeight() {
 var g = document, a = g.body, f = g.documentElement, d = g.compatMode == "BackCompat"
 ? a
 : g.documentElement;
 return Math.max(f.scrollHeight, a.scrollHeight, d.clientHeight);
}

47. 原生JavaScript获取页面scrollLeft

function getPageScrollLeft(){
 var a = document;
 return a.documentElement.scrollLeft || a.body.scrollLeft;
}

48. 原生JavaScript获取页面可视宽度

function getPageViewWidth(){
 var d = document, a = d.compatMode == "BackCompat"
 ? d.body
 : d.documentElement;
 return a.clientWidth; // 可视宽度为clientWidth
}

49. 原生JavaScript获取页面宽度

// 考虑带滚动条的全部宽度
function getPageWidth(){
 var g = document, a = g.body, f = g.documentElement, d = g.compatMode == "BackCompat"
 ? a
 : g.documentElement;
 return Math.max(f.scrollWidth, a.scrollWidth, d.clientWidth);
}

50. 原生JavaScript获取页面scrollTop

function getPageScrollTop(){
 var a = document;
 return a.documentElement.scrollTop || a.body.scrollTop;
}

转载于:https://www.jianshu.com/p/486a89ed0051